This invention relates to the field of energy collectors usable for collecting of solar energy and other radiant energy and provides a substantially improved energy collector module which is readily gangable with a plurality of like modules with a minimum of labor at the final construction site.
With increased interest in solar energy utilization for the heating of buildings, efforts have increased to develop a solar energy collector module capable of absorbing as much incident solar energy as possible while minimizing the quantity of energy escaping the collector. Beside the need to improve the quality of individual solar collectors, it is desirable to make such collectors compatible with other collectors so that quantities of individual collectors can be ganged.
While it is known to gang a plurality of solar collectors, the problems associated with ganging have been sufficient to discourage large scale commercial production of gangable solar collectors. Presently, individual solar collectors are commonly assembled and ganged at the construction site and the insulative housing which must surround the collectors to retain captured energy is often assembled and insulated under field conditions which invariably do not approach the quality control standards which can be maintained in a factory assembly environment. It is usually extremely difficult to effectively close, thoroughly insulate and reliably seal the insulative housings of collectors at the construction site and the result is that housings so constructed are commonly drafty, unreliable, and subject to substantial heat loss to the ambient environment.
The presently known gangable collectors utilize a collector and a pair of continuous ducts which extend from an insulative housing surrounding the collector. One shortcoming of such a structure is that their continuous ducts which extend through the walls of the housing define a heat sink along which heat from within the housing is conducted from the inside of the housing to the outside, where it is lost to the atmosphere. It would be desirable to have a ganging apparatus which minimizes such heat loss.
Still another problem associated with presently known gangable collectors is that the continuous ducting already described and which attaches to a solar collector within the housing, undergoes substantial thermal expansion and contraction is response to temperature changes in the housing. Such thermal expansion causes movement of the ducts relative to the housing and eventually causes breakdown of the insulative seal between housing and duct, thereby substantially reducing effectiveness of the insulative housing. When a plurality of such gangable collectors are connected, the presently used continuous and relatively rigid ducts are easily jarred or twisted and such jarring can damage the seals between duct ahd housing and can cause interior breakage between collector and ducts. It is desirable to provide a gangable collector capable of absorbing some rough handling at the construction site without damage to the integrity of its insulative housing or interior connection.
Still another difficulty encountered in the ganging of a system of collectors is that the commonly used liquid or gaseous heat transfer medium tends to circulate more readily through solar collectors near the location at which the heat transfer medium is pumped into the system and tends to resist circulation through solar collectors further downstream. It is difficult at the time of manufacture to design or adjust individual collectors to work well in combination with a particular number of ganged collectors because usually it is not known at the time of manufacture how many solar collectors will be ganged and in precisely what arrangement. Because of these uncertainties, extensive adjustment and manipulation of collectors has been necessary at the construction site in order to make the ganged solar collectors function efficiently as a group. In the past, such adjustment has required opening the insulative housings of individual collectors to make internal adjustments relating to flow of heat transfer medium, and opening the housings reduces the quality of the insulation therein and the overall effectiveness of the housing. Accordingly, it would be desirable to provide a solar collector which may be easily adjusted at the job site to facilitate its placement in tandem with other collectors but without the requirement of opening the housing.
Still another problem encountered with many known solar collectors is the often extension internal convection currents which occur within the housing and which tends to cool the collector. The output side of the solar collector will always be at a higher temperature than the input side and this imbalance generates convection currents therebetween. It is desirable to minimize these convection currents to make the collector more efficient. These problems and the earlier described shortcomings of most known collectors are substantially alleviated by the invention disclosed herein.